The present invention relates to a novel negative-working radiation-sensitive resist composition or, more particularly, to a negative-working radiation-sensitive resist composition capable of exhibiting high resolution of patterning and high sensitivity to actinic rays to be suitable as a resist material for very fine patterning works in the field of electronic industries such as manufacture of various kinds of semiconductor devices and still capable of giving a patterned resist layer having a quite satisfactory cross sectional profile with high orthogonality.
Along with the rapid progress in recent years in the technology of manufacture of semiconductor devices with a trend toward more and more increased density of integration, the fineness in the fine patterning works is required to have a resolution in the sub-micron order. In the so-called photolithographic process as a major current in the fine patterning works for the manufacture of semiconductor devices, the resolution required for the fine patterning work is as small as 0.5 .mu.m or even smaller so that it is a trend that the pattern-wise exposure of the resist layer is conducted by using ultraviolet light of a shorter and shorter wavelength such as the so-called deep ultraviolet light, i-line and g-line emitted from various kinds of ultraviolet light sources in the wavelength range of 200 to 500 nm, eximer lasers and KrF lasers emitting at a wavelength of 248 nm. Further, development works are under way for the use of X-rays and electron beams as the actinic rays for fine patterning.
Radiation-sensitive resist compositions used in such a photolithographic patterning work naturally must comply with the decreasing trend in the wavelength of the actinic rays for the patterning exposure. Various proposals and attempts have been made in this regard also for negative-working radiation-sensitive resist compositions. For example, Japanese Patent Publication 62-8777 discloses a resist composition comprising a phenol novolac resin and a bisazide compound having sensitivity for deep ultraviolet light, i-line and g-line and a resist composition comprising a chloromethylated polystyrene or polyvinyl phenol and a bisazide compound having sensitivity to excimer laser beams, Japanese Patent Kokai 62-164045 discloses a resist composition comprising a thermosetting resin and a halogenated organic compound, which absorbs chemical lines in the wavelength region of 210 to 299 nm, as a photoacid-generator having sensitivity to excimer laser beams, deep ultraviolet light and X-rays and resist compositions having sensitivity to electron beams are disclosed in Japanese Patent Publication 45-30285, Journal of Electrochemical Society, volume 118, page 669 (1971) and Japanese Patent Kokai 57-176034, of which the film-forming resinous ingredient is a polymethyl methacrylate, polyglycidyl methacrylate or chloromethylated polystyrene, respectively.
These negative-working radiation-sensitive resist compositions in the prior art, however, have a problem that the patterned resist layer obtained by using such a composition does not have a desirable orthogonal cross sectional profile with trailing skirts resulting in poor resolution of the pattern if not to mention their relatively low sensitivity to deep ultraviolet light, i-lie, g-line, excimer laser beams, electron beams and X-rays not to meet the requirements in the modern patterning works. Thus, none of the negative-working radiation-sensitive resist compositions can be used in the photolithographic patterning works in which a resolution of 0.5 .mu.m or even finer is required by using short wavelength actinic rays. Accordingly, it is eagerly desired in the technology of semiconductor devices to develop a negative-working radiation-sensitive resist composition capable of giving a patterned resist layer having high resolution and a desirable orthogonal cross sectional profile and still having high sensitivity to various kinds of actinic rays.